Prostaglandins (PGs) have been associated with the onset of labor in women. Naturally occurring PGs are potent stimulants of human uterine contractility at any stage of pregnancy and also cause cervical ripening.
Induction of labor is defined as the process of artificially stimulating the uterus to start labor. It may be performed by administering oxytocin or prostaglandins to the pregnant woman. Labor induction is one of the most frequent procedures in pregnant women.
Cytotec and Misofar are commercially available misoprostol products, which comprise an extended release agent, hydrogenated castor oil.
The International patent application WO 2006/125450 A1 mentions the possibility of oral, sublingual, rectal or vaginal administration of misoprostol used in obstetric practice for controlling post-partum and post-abortive bleeding, and inducing labor or abortion. This application fails to disclose a pharmaceutical dosage form suitable for the mentioned administration forms.
The International patent application WO 2006/133048 A2 relates to a controlled release pharmaceutical gel for vaginal administration, the pharmaceutical gel comprising misoprostol, a cellulose derivative and a polyol, wherein the gel is a substantially nonaqueous gel which forms a hydrogel when placed in a vaginal tract.
The International patent application WO 2014/016394 A1 relates to the use of misoprostol for the induction of labor in a pregnant female, and in particular to the use of a sustained delivery device or insert containing 200 μg misoprostol for intravaginal use.
The International patent application WO 2007/035953 discloses vaginal tablets comprising misoprostol. The disclosed tablets comprise 100 μg misoprostol. A purported immediate release vaginal tablet and a sustained release vaginal tablet are disclosed, wherein the purported immediate release vaginal tablet are described as adhering to a tilted glass plate when placed on drops of water. Embodiments of the tablets are purported to adhere to an epithelial membrane. The vaginal tablets comprise lactose monohydrate, hydroxypropyl methylcellulose, corn starch and magnesium stearate. The vaginal tablets are manufactured by method steps comprising wet granulation, followed by drying in a fluid bed. The disclosed indications comprise cervical ripening and uterine contractions but not human labor.